Pedestrian access to boats moored in a marina is often provided between a pier or other waterfront structure and the boats by means of a floating dock having a pedestrian walkway extending along side a row of mooring stations for the boats. Consequently, the need arises for a pedestrian bridge between the pier and the floating dock to complete the walkway between the boats and the shore. Pedestrian bridges known to be used for this purpose generally comprise a ramp extending at an incline between the floating dock and the raised pier. Such ramps may be of wooden construction, but in order to span extended distances across the water without intermediate structural supports such as trusses or columns associated with more elaborate bridge structures, the ramps are commonly formed of steel or aluminum. However, metal ramps suffer from several disadvantages as they are somewhat incompatible with the conditions surrounding use of a pedestrian walkway in a marine environment.
Specifically, metal ramps are known to be formed in a single unitary piece extending between the opposite ends. Unless custom made, they are consequently manufactured and available only in standard lengths and widths. This may often require that the location and dimensions of the floating dock be made to accommodate the available ramp dimensions, as opposed to the converse situation wherein a ramp will be selected to meet the preferred location of the floating dock. This is an important consideration in the construction of a pedestrian walkway between the shore and the moored boats since the location of a floating dock is determined in consideration of the layout of the entire marina, and should not be critically dependent upon a single element such as the pedestrian ramp. Furthermore, known unitary ramps of any substantial length are extremely costly to ship from the factory to the site, particularly when the elongated ramps dominates the space available on a truck or rail car.
Other disadvantages of known steel or aluminum pedestrian ramps are caused by the metal material itself. Metal is obviously a heavy material which makes handling and installation of the ramp difficult in most circumstances. Beyond the usual problems associated with excessive weight, there is the additional problem of maintaining floatation when one end of the ramp rests atop a floating dock. The dock should be at least generally level along its length in order to provide a convenient pedestrian walkway, and likewise should rise and fall in response to wave action consistently along its length. An excessive weight load imposed at one spot by the ramp could easily interfere with those floatation features of the dock. Furthermore, metals tend to corrode in both fresh and salt water environments, and as electrical conductors they may pose a particular safety hazard with respect to lightning or electrical utilities extended from the shore outwardly to the floating dock.
The prior art is thus seen to fail to provide a pedestrian ramp for spanning the water between a floating dock and a pier or other land based structure which is adaptable in length and width to accommodate existing dock and pier conditions, or which is lightweight and electrically nonconductive.